Hey all I have a English o2 3g iphone and am off to the states for a month or so in the summer and I have a few questions if anyone can help. I guess I have two options, use my o2 SIM or buy an ATT one. My question is, has anyone tried this? Am not to worried about phone calls-ill be using Skype over WIFI for that, but am more concerned with data, email and MOSTLY Google maps (I may get lost!) Does anyone know the best/cheapest way to proceed? Any help greatly appreciated.